The present invention relates to methods, and compositions for providing more vibrant, natural and long-lasting color to hair. The term vibrant as used herein refers to an optical quality in which the hair has a deep color yet appears bright as if light were emanating from within the hair fibers and not only being reflected at the surface. The method comprises two essential steps: contacting the hair for a period of time with a dye precursor mixture containing specific primary intermediates and couplers at defined pH conditions which control their state of ionization and developing the color by contacting the hair with a developer mixture. The invention also relates to kits providing the means to accomplish these steps.
Permanent hair colorants commonly come in two parts: a dye solution and a developer solution. In a conventional permanent hair coloring treatment, the dye solution and the developer solution are mixed and then immediately applied to the hair. After a time interval of about 25 to about 45 minutes, the hair is rinsed with water, treated with a post treatment conditioner, and then rinsed again with water.
The application of the dye solution and the developer solution affords permanent hair coloring. However, use of this conventional method does not provide maximum color deposition or retention and the range of color nuances especially in the red shades is limited.
The duration over which dyed hair remains colored is in principle only limited by the hair growth rate assuming the treatment does not affect the color of the hair as it is formed, i.e., the “roots”. In practice dye films deposited on the hair are susceptible to extraction by repeated shampooing, erosion by combing and brushing, and fading by exposure to sunlight and oxygen. Red colors are particularly susceptible to these degrading processes and in an attempt to achieve sufficiently deep and long lasting red shades consumers often try to compensate by increasing the intensity of the initial color. However, this can lead to hair that has an unnatural or painted appearance.
The underlying problem in achieving vibrant and natural colors especially dark reds, that are also long-lasting and fade resistant, through oxidative dyeing of hair is that only a small portion of such colors enters the interior of the hair fiber during the dyeing process. As is well known, the color of oxidative dyes arises from the oxidative coupling of primary intermediates and secondary intermediate (often called couplers)—essentially dimerization and/or polymerization. Thus, oxidative coupling leads to an increase in molecular weight as well as an increase in conjugation. However, as the molecular weight rises, it becomes increasingly difficult for the polymerized dye to penetrate the hair fibers. Thus, the darkest colors are more likely to remain at the surface of the hair fibers where they are most susceptible to erosion, and abrasion. Being on the outside of the fibers these colors are also in an “optical environment” that is least similar to the environment of the natural melanins in hair, i.e., dispersed within the hair fiber matrix. The term “painted” often used to describe the unnatural appearance of darkly dyed hair is more than coincidental!
One objective of the present invention of the invention is a method of coloring the hair, especially coloring hair a reddish color that will provide a more vibrant and natural looking color.
An additional objective is a method of coloring the hair that will provide greater resistance to erosion, abrasion and chemical fading.
A still further objective is to provide a convenient kit that can be used by individual consumers to practice the method at home.
These and other objectives will become clear from the description of the invention.
The following patents and publications have been considered:
U.S. Pat. No. 2,934,396 discloses a two-step process for coloring the hair utilizing an acid solution of 5,6 dihydroxyindole followed by application of a solution containing an oxidizing agent.
U.S. Pat. No. 3,194,734 discloses a two-step process for coloring the hair utilizing an acid solution of 5,6 dihydroxyindole derivatives followed by application of a solution containing an oxidizing agent.
U.S. Pat. No. 4,104,021 discloses successive applications of a mixture of coupler (aromatic primary amines and aminophenols) and an oxidizing agent with each treatment having an increased level of oxidizing agent.
U.S. Pat. No. 4,370,142 discloses the dyeing of hair with a mixture of para-phenylenediamine, ortho-aminophenol, and hydrogen peroxide.
GB 2205329 A discloses a process comprising treating hair with a mixture of an oxidation base and iodide ions and subsequently treating hair with a solution of hydrogen peroxide at pH 2–12.
U.S. Pat. No. 4,804,385 discloses a process comprising treating hair with a mixture of an 5,6 dihydroxyindole and iodide ions and either subsequently or before treating hair with a solution of hydrogen peroxide.
U.S. Pat. No. 4,888,027 discloses a process comprising treating hair with a mixture of an 5,6 dihydroxyindole and iodide ions and subsequently treating the hair with an alkaline solution of hydrogen peroxide.
U.S. Pat. No. 5,173,085 discloses a process comprising treating the hair with an aqueous solution of a metal salt, followed or preceded by treatment with 5,6 dihydroxyindole, rinsing and finally treated with a aqueous solution of hydrogen peroxide.
EP 0755 669 B1 discloses a two step process wherein the hair is first treated with a solution containing magnesium ions followed by treatment with a mixture of an oxidation base and an oxidizing agent.
U.S. Pat. No. 5,980,586 discloses a process for dyeing the hair with a mixture of an aminoethanethiol, dihydroxybenzene, and a ferricyanide or persulfate.
WO 01/28508 A1 discloses a composition and method for coloring hair comprising an oxidizing agent, an oxidative or non-oxidative dye used in combination with ammonium carbonate or carbamate.
WO 02/02062 discloses the use of acid salts to increase the absorption qualities of anionic direct dyes in the coloring of fibers and a procedure for accomplishing this.
U.S. Pat. No. 5,525,123, discloses a hair dyeing composition based on oxidation dyestuff precursors at least one developer, coupling agent, metal salt, and an ammonium compound.
U.S. Pat. No. 5,279,620 discloses mixtures of oxidation colorants and certain indole coupler.
Co-owned and co-pending Ser. No. 09/811,920 filed Mar. 19, 2001, incorporated by reference herein, discloses a method for permanently dyeing hair which comprises subjecting hair to a number of treatments, having a set time interval between each of the two consecutive steps.
Co-owned and co-pending Ser. No. 10/075,745 filed February 14 2002, incorporated by reference herein, discloses a method for permanently dyeing hair which comprises contacting the hair with a substantially inactive mixture including one or more oxidation dyes followed by application of a developer which oxidizes the dye.
None of the references cited above teaches that a sequential method for coloring the hair in which specific dyes in a non-anionic, preferably nonionic, and substantially oxidatively inactive form are first contacted with the hair followed by a developer lead to more vibrant colors and more varied tones.